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Method for purifying m-phenylenediamine

A technology of m-phenylenediamine and purification method, applied in the direction of amino compound purification/separation, organic chemistry, etc., can solve the problems of large reflux ratio, high equipment investment and operation energy consumption, and many theoretical plates, etc., to improve the utilization rate , Reduce separation energy consumption and equipment investment, the effect of scientific principle

Active Publication Date: 2017-10-24
QINGDAO UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional purification method of m-phenylenediamine mostly adopts rectification method, but because the boiling point of impurity diaminotoluene is too close to that of m-phenylenediamine ((2,4-diaminoaniline boiling point~292℃, 2,6-diaminoaniline Boiling point ~289°C, m-phenylenediamine boiling point ~285°C)), so distillation and separation are more difficult, requiring more theoretical plates and a larger reflux ratio, higher equipment investment and operating energy consumption, and removal of impurities The efficiency is not high, resulting in limited purification effect of m-phenylenediamine

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1: a kind of purification method of m-phenylenediamine, specifically comprises the following steps:

[0022] (1) The total content of diaminotoluene in m-phenylenediamine ashes is about 240ppm, of which about 80% is 2,4-diaminotoluene and about 20% is 2,6-diaminotoluene; The diamine ashes are continuously sent to the rectification tower with a theoretical plate number of 50; continuous rectification at 3kPa, the temperature at the top of the rectification tower is controlled at 162°C, the temperature at the bottom of the tower is 178°C, and m-phenylenediamine passes through the tower After the top condenser is cooled, the part is returned to the top of the tower through the reflux pipe as the reflux liquid, and the reflux ratio is controlled to be 5, and the liquid accounting for 60% of the total liquid quality is extracted through the m-phenylenediamine extraction pipe;

[0023] (2) Inject the mined m-phenylenediamine directly into the crystallizer, heat unt...

Embodiment 2

[0025] Embodiment 2: a kind of purification method of m-phenylenediamine, specifically comprises the following steps:

[0026] (1) The total content of diaminotoluene in m-phenylenediamine ashes is about 220ppm, of which about 80% is 2,4-diaminotoluene and about 20% is 2,6-diaminotoluene; The diamine ashes are continuously sent to the rectification tower with a theoretical plate number of 60; continuous rectification at 5kPa, the temperature at the top of the rectification tower is controlled at 180°C, the temperature at the bottom of the tower is 200°C, and m-phenylenediamine passes through the tower The cooled part of the top condenser is returned to the top of the tower through the reflux pipe as the reflux liquid, and the reflux ratio is controlled to be 8, and the liquid accounting for 45% of the total liquid mass is extracted through the extraction pipe;

[0027] (2) Inject the mined m-phenylenediamine directly into the crystallizer, heat until it is completely molten, c...

Embodiment 3

[0029] Embodiment 3: a kind of purification method of m-phenylenediamine, specifically comprises the following steps:

[0030] (1) The total content of diaminotoluene in m-phenylenediamine ashes is about 190ppm, of which about 80% is 2,4-diaminotoluene and about 20% is 2,6-diaminotoluene; The diamine ashes are continuously fed into the rectification tower with a theoretical plate number of 70; continuous rectification at 1kPa, the temperature at the top of the rectification tower is controlled at 150°C, the temperature at the bottom of the tower is 170°C, and m-phenylenediamine passes through the tower After the top condenser is cooled, the part is returned to the top of the tower through the reflux pipe as the reflux liquid, and the reflux ratio is controlled to be 10, and the liquid accounting for 30% of the total liquid quality is extracted through the m-phenylenediamine extraction pipe;

[0031] (2) Inject the mined m-phenylenediamine directly into the crystallizer, heat u...

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Abstract

The invention relates to the technical field of production of m-phenylenediamine and particularly discloses a method for purifying m-phenylenediamine. The method for purifying m-phenylenediamine is characterized by comprising the following steps: continuously feeding pre-molten m-phenylenediamine ash into a rectifying tower to be rectified, and extracting partial liquid through an extraction pipe; directly injecting the extracted m-phenylenediamine into a crystallizer, heating until the m-phenylenediamine is totally molten, cooling, crystallizing and cooling, draining the mother solution by a drain valve of the crystallizer, feeding to the next-stage crystallizer to be continuously molten and crystallized, wherein the operation process is the same as that in the previous step; and collecting the feed liquid obtained by multistage melting and crystallizing, cooling and slicing in an inert protection atmosphere, thereby obtaining the finished purified m-phenylenediamine product. According to the m-phenylenediamine purified by the method disclosed by the invention, the content of the impurity, namely diaminotoluene, in the m-phenylenediamine is less than 50ppm, the requirements on synthesis of aramid fibers 1313 and other high-purity applications can be met, the principle is scientific, the utilization rate of the materials is improved, the separation energy consumption and equipment investment are reduced, and the method is green and economical.

Description

(1) Technical field [0001] The invention relates to the technical field of m-phenylenediamine production, in particular to a method for purifying m-phenylenediamine. (2) Background technology [0002] m-Phenylenediamine is an important dye intermediate, which can be used to synthesize various basic dyes, and it is also an important aromatic amine curing agent, which is widely used in the fields of composite materials and plastics. With the rapid development of polyarylamide high-performance materials and aramid materials in recent years, the use of m-phenylenediamine has been newly expanded. It has broad market prospects in the synthesis of high-temperature-resistant aramid fiber 1313, and also New requirements and challenges have been put forward for the preparation of high-quality m-phenylenediamine. [0003] The chemical properties of m-phenylenediamine are relatively active, and it is easy to be oxidized and deteriorated. It is also easy to generate other impurities dur...

Claims

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Application Information

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IPC IPC(8): C07C209/84C07C211/51
CPCC07C209/84C07C211/51
Inventor 丁军委于文龙于世涛刘仕伟
Owner QINGDAO UNIV OF SCI & TECH
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